Art of reclaiming lubricating oils



O. J. NELSON Nov. 12, 1929.

ART OF RECLAIMING LUBRICATING OILS Filed Jan. 8, 1923 kvk um en. om,

M. O w E .Jh WL/ L 1w 0%# wa Patented Nov. 12, 1929 UNITI-:D STATES PATENTv OFFICE OLIVER J. NELSON, OF ST. LOUIS, MISSOURI, ASSIGNOR TO BRYTE-NELSON IREFINING COMPANY, OF ST, LOUIS, MISSOURI, A CORPORATION OF MISSOURI ART F RECLAIMING LUBRICATING OILS This invention relates to the reclaiming of .lubricating oils, and more particularly those oils having a mineral base and which have been used in crank cases of gas engines.'

The lubricating oil used in crank cases has a mineral base but the composition of this lubricant base varies. Thus Where it is obtained from a parafiin base petroleum, it is the residue remaining after distillation of the lighter and heavier hydrocarbons, While if the petroleum has an asphalti'c or mixed base,

it is the distillate following the volatilization of the` napthas and kerosene. In the compounding of lubricating oils, the viscosity and body are often raised by the addition of cylinder stock, animal fats and oils and vegetable oils. Sometimes even soaps and mere adulterants are added. Accordingly in a given crank case the mixture may be complex not only from the standpoint of the original mineral oils due to the constant addition of different grades and makes, but the mixture may also contain compounds other than mineral oil.

The oil in a crank case is subject to unusual treatment While in use. Upon reciprocation the oil is splashed on the cylinder Walls and is I caused to spread over the same in a film. As

this film is exposed to high temperatures, the

oil may be cracked and this cracked product is then Washed down into the crank case, not

only by the wiping action of the piston and the'washing action of the oil, but also by the action of unvolatilized fuel and condensed moisture which enter the crank case past the pistons. The oil in the crank case is furthermore subjected to considerable heat due to conduction as Well as escape of gases from the combustion chamber into the crank case.

40 Since the oil is churned and exposedto air under the influence of heat', the result is an oxidation and polymerization so that asphaltic and resinous compounds are formed.

With the employment of the lower grade fuel now used and the tendency of running an engine cold, frequent priming and missing of cylinders, a good deal of the volatile hydrocarbons are Washed down into the crank case,

diluting the oil therein to such' an extent that the body may contain as much as fifty percent (50%) of lighter hydrocarbons, thereby reducing the viscosity to such an extent that it may only be one-twentieth (1/20) of that of the original oil. These lighter hydrocarbons are found in practice to be about mid-way between gasoline and kerosene.

Solid matter, such as carbon, metal grindings and particles, earthly matter and sand also enter the crank case. Furthermore vmoisture Will frequently enter with the fuel,

as When a cylinder is missing or Whenstarting. Accordingly under the churning action in the crank case, complex emulsions and colloids 4are formed, more especially where animal fats and alkalis are present, as is frequently the case Where the viscosity and body are raised by the addition of fats and soaps.

The result, therefore, is that the mixture in a crank case is a very complex one. Moreover Where the oil from a number of crank cases is dumped into a common vat, the result-ant mixture is even more complex.

It has been attempted to reclaim the oil from such a mixture, but previous processes have not on the Whole been successful in View of the fact that the complex nature and the required treatment have not been fully appreciated and understood. Such a complex mixture cannot be treated like the original petroleum, Whether of a paraiin, asphaltie or mixed base, because the mixture contains various foreign substances and is ina different condition than is the case with petroleums. A mere filtering or acid treatment is not sufficient; nor can the ordinary processes of distillation be utilized. The reclaiming of such a used lubricating oil, containing as it does solid matter, moisture and lighter hydrocarbons partially emulsied and polymer-ized, requires knowledge of the composition and nature of the mixture and the treatment necessary in order to meet the conditions.

It has been found by experiment that the lubricating property of the mineral base is not damaged by use, even under the strenuous conditions encountered in a crank case, but that the value of the mineral base has been rather enhanced. because what has remained behind has been due to the survival of the fittest part. The complex mixture, however, requires the most careful treatment.

From an economic stand point the reclamation of such lubricating oil is exceedingly important for the reason that the oil under the adverse conditions in the crank case loses its lubricating value very readily so that it must be changed and discarded with great frequency. Accordingly there are millions of barrels of such lubricating oil discarded every year, whichis not only a loss to the industry, but its'disposal is moreover troublesome and costly since it cannot be run into sewers on account of the danger of explosion and fire.

One of the objects of this invention, therefore, is to provide a process of treatment of such a lubricating oil whereby the mineral base will not only be reclaimed and regenerated, but conservedv in such a manner as to obtain as' result a' lubricant which is even of a higher grade than the original lubricants.,

Further objects will appear from the detail description taken in connection with the accompanying drawing, in which the figure is an elevation partly in section. The description and drawing illustrate an embodiment of this invention. It will 'be noted, however, that in' the drawing parts have not only been illustrated diagrammatically but not necessarily at the proper elevations, as this drawing is simply for illustration and is not intended to show the actual arrangement and location of the elements of the plant.

In accordance with this invention, the used lubricating oil is subjected generally to the following treatments, namely a defecating or` v clarifying treatment, a distillation treatment and a filtering treatment. Furthermore the body is also allowed to cool between the distillation and filtering treatments.

The character of the clarifying or defecating treatment depends upon the character and condition of the oil and upon the foreign bodies which it contains as well as upon the nature of the incorporation of these bodies within the mineral oil base. If the oil body contains only solid particles and mechanicallyentrained Water, a simple centrifuging may be sufficient, especially if it is preceded by a heat treatment, especially by an agitating heat treatment with steam.

Usually, however, the oil body contains the solid matter and the water in a difficult separable form and more especially in the form of complex emulsions or colloids, so that mere centrifuging even if preceded by heat treatment is not sufficient. In such a case the oil body is subjected lto an acid treatment while agitated with air, followed by an alkali treatment while agitated with air and then steam, followed by settling, the upper portion being then again agitated with live In the distilling treatment, the body of oil is gradually heated over an extended period, the first stage being a rather gentle heat, while the body is gently agitated with air followed by more violent agitation with air. Live steam is then gradually blown into the body along with the air and thereafter the air is gradually cut down while the steam is increased untilnothing but steam enters the body. The steam is now superheated, preferably by the heat of the body of oil itself, untilthe temperature rises preferably above the vaporizing point of the mineral base so that some of this mineral base begins to pass over with the steam. The heating is now interrupted and the oil body is allowed to settle slowly in order to cool to a temperature considerably below the volatilization point of the mineral base. The oil body is then drawn from the still and cooled to a point where it will notignite.

The cooled oil body isnow'ltered, ref-. erably through fullers earth and this ltering is under pressure and at a temperature suflicient to cause the oil to flow through the lter.

In order to more clearly describe the invention, an example of a practical embodiment of this invention and of a plant illustrating a pratcical embodiment for carrying out the process will be given; it is to be understood, however, that ,the construction and arrangement may be varied without departing from the spirit of this invention. Furthermore it Will be understood that the drawing is illustrative only and in somewhat diagrammatical form and that it does not necessarily show the parts in their true posi-r tions. Furthermore pipes and valves are shown in conventional form and will not be referred to in. detail.

Referring now to the accompanying drawing, 1 designates a vat of a suitable construction to permit treatment of the oil with sulphuric acid and alkali. It is provided with a perforated pipe 2 which may have an air connection 3 and a steam connection 4, whereby either air or steam or both may be blown through the connections therein. Suitable supply lines 5 and 6 may be provided for a mineral acid, such as sulphuric acid, and an alkali, such as caustic soda. The vat discharges into a settling tank 7 and .from this tank the upper portion is taken by a pipe 8 to a treating tank 9 provided with a heating coil 10, receiving steam from the boiler 11. This tank also contains a perforated pipe 12 also connected to receive steam. The vat 9 discharges into a steam operated centrifuge 13 which in turn has a spout 130 discharging into a storage tank 14.

From the storage tank 14 a pump 15 delivers the body to a still 16, which is preferably arranged on a brick foundation of a furnace having a combustion chamber 17 heated by a fuel burner 18, which may be either of the oil or gas type. The still is provided with a heating coil 19 connected with the steam pipe 20 and with the exhaust 21. The bottom of the still further has arranged therein a perforated pipe 22, the perforations of which extend along the lower side so as to direct jets of air or steam on the bottom of the still, and this pipe has suitable valve connections with the steam pipe 20 and the exhaust 2l and a suitable air connection with an air pipe 23. The top of the still has a large vapor pipe 24 which is horizontally arranged and of large capacity and connectswith an upper branch 25 and a lower branch 26 connected by legs 27. The branches 25 and 26 are practically horizontal, draining slightly to the right or away from the still. The outlet 24 as well as the top and side of thefurnace are preferably jacketed with` an insulating material to retain the heat and thus avoid condensation. The bottom of the still has an outlet 28.

From the still the pipes 25 and 26 lead to a condensor 29 which may be of the water cooled type and from this condensor the condensates are led to storage tanks 30.

The body .of the oil is taken from the still by a pump 31 through cooling coils 32 into a storage tank 33. From the storage tank a pump 34 takes the oil to the pressure filters 35. These filters contain a suitable filtering material 36 such as fullers earth, and' each is provided with a steam heating coil 37 and with an air pressure connection 38.

Assuming that used lubricating oil from crank cases is the body to be treated,'and that this oil contains impurities and is in the condition as previously described, the general operation of a practical embodiment of a process embodying this invention is as follows:

The usual lubricating oil is placed in the tank or vat 1 and sulphuric acid' of about 66 B. is added in the lproportion of about live Y to seven pounds to a barrel of the oi-l. This is then agitated with air for about two hours. The function of this treatment is to partially dissolve any metal particles, break up the emulsions and colloids, and cause precipitation of the solid matter due to the breaking up of the emulsion. The acid treatment furv ther acts to break up the polymerzed products and more especially those of an asphaltic and a resinous nature. The body is now neutralized with a concentrated caustic soda solution of 30 to 33 B. and is agitated first with air and then with live steam for about two hours at a temperature of about 105 F. This treatment not only neutralizes the sula phuric acid and other acids which may be resent, but the steam in condensing also diutes the alkali and all dissolved lmpurltles tom while the less dense part containing the oil floats on top. The upper portion is no w removed to the vat 9 where it is agitated and heated with live steam to about 150 F. This thoroughly mixes the 'different components of the oil. It not only renders the body more suitable `for the subsequentcentrifuging but Q further serves to assist in the breaking up of the emulsion, especially those that may be formed by the addition ofthe causticv soda and by the treatment withlive steam.

The body is now subjected to the action of the centrifuge 13 which further serves to remove the heavier impurities and water and serves to additionally effect breaking up of the emulsions. It is, however, found 'that even all of the impurities and water will not be removed but that aboutfive percent may remain. The centrifuge discharges into vthe vat 14 which is simply a storage vat."

The body is now pumped into the stilly 16 which is filled 85% full. It is now. first Vsubjected to a slow heat while the body is agitated with air for a period of about twenty minutes, until the temperature` is -raised slightly above the boiling point of water, that is, to about 212 to 21-5 degrees F. During this procedure the body is gradually heated and some of the volatile matter in the form of dissolved gases may pass off and some moisture is also freed. Some of the emulsion may also be partially broken up and carried ofi with the air. This air performs theI functionof not only keepingthe mass in motion so as to cause uniform heating, but water settling to the bottom will be blown up through the The still is now heated sothtits tempera-.

This air will v-alsoi 'prevent ture will be gradually elevated overa period of about three hours from 215 F. to 700- F. During this gradual heating the procedure is as follows and the oil passes through various stages: v

While they temperature is rising from 215 to 265 F., the body is blown with air at a pressure at about 10 to 15 pounds per square inch. This serves not only to blow out moisture but also carry out all'entrained gases.

It also causes oxidation of any oxidizable products which may be present and which, when formed into gas, are carried off with the air. The direction of the air blasts on the bottoni of the still furthermore prevents coil 19 and then into the pipe 22.

i back into the hot oil.

burning of the oil where it is in contact with the hot walls next to the fire. i

Vhen the temperature reaches 265 F., livey steam is passed in with the air so that both steam and air will issue from the pipe 22. I'Vhile the temperature is rising from 265 to 320 F., the air is gradually cut down while the live steam is increased until at the end of this particular stage and When the temperature reaches 320 F., live steam alone will issue from the pipe and will be directed against the bottom of the still, thereby not only securing thorough mixing of the oil but also preventing scorching. 5

During this stage the lighter hydrocarbons, such as gasoline and naptha are volatilized and pass out with the steam, and since these lighter hydrocarbons pass out during the latter part of the stage, the presence of the Wet steam will prevent inition and explosion of these lighter ydrocarbons. Of course, the presence of the steam will reduce the bolling point of the lighter hydrocarbons so that they will be volatilized at a lower tem- )erature than if the steam Were not present.

his is important in the reclamation of lubricating oil, since it is necessary that the heat be as 'low as possible in order that as little decomposition may take place as possible, 1n order to obtain the highest viscosity and the least amount of cracking. The steam in stirring the oil further prevents local overheating and the vapors as soon as formed are carried oil' by'the steam so that they do not fall Furthermore the arrangement of the pipe 24 and the jacketing of the same are such that the gases will pass out freely Without any liability of condensing and falling back into the hot oil. In this Way cracking is entirely avoided, whic-h is desil-able since cracking not only reduces the lubricating oil content but also causes the formation of objectionable asphaltic and resinous products.

W'hen the temperature reaches 320 F. the

live steam connection to the pipe 22 is cut off and the steam is passed first through the This causes the steam before it issues fromthe pipe `22V to pass through the body of the oil so that it will become superheated. During this stage the temperature rises to 700 F. and at the end of the stage the pressure rises to 125 pounds per square inch. Accordingly the steam has a superheat of 350 F. During this stage the heavy napthas and kerosene and animal fats pass off and are carried over with the steam and there is also a complete breaking up of any asphaltic and resinous matter which may be present. The distillation is continued until the mineral base begins to' pass over, which is determined by the distillate having a gravity of from 30 to 32 B., and by the fact that half of the vapors passingover is steam.

At the end of this stage all ofthe hydrocarbons and fats as Well as water, which are more volatile than the mineral base, will have been distilled from the body, while any other impurities present will be completely broken up. The still contents are now allowed to settle until the temperature drops to 500 F., a little steam in a superheated condition,'being passed through the body in order to keep up the temperature and keep the mass in agitation so that this cooling down is extended over a period of about one hour. only prevents cracking but insures that all the This not hydrocarbons and fats of lower volatilrization f than the mineral base will have passed oli", that other impurities Will be completely broken up and separated from the mineral base and that the whole is mixed and worked to form a uniform mass. still through cooling coils 32, which reducesv the temperature to about 100 F. and thence to a storage tank 33.

The oil is pumped from the storage tank 33 to the filters 35 containing fullers earth, through which the oil is passed under pres- The oil is novi1 drawn from the' sure of about seventy-five pounds per square a purified product whose viscosity was found to be 280 seconds (Saybolt), and had a flash point of 500 F., a fire test of 525 F. and a density of 291/2 to 30 B.

While certain theories of operation have been advanced, it is to be understood that the purpose has been one of explanation and not of limitation, since it is not essential that the operation be dependent upon any theory, for the description of the above process is of an actual practical and existing embodiment. It

is, therefore, to be understood that this invention is -not to be limited to any theory advanced. Itis further obvious that various changes may be made in details Without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to any details described or shown.

Having thus described the invention, what is claimed is:

1. In the art of reclaiming used mineral lubricating oil containing solid matter, moisture, fats and lighter hydrocarbons, and

. partially emulsified and polymerized, the

process'comprising, defecating the oil to clearl the same of the solid matter and entrained water,V heating the defecated oil at a temperatue'and for a period suilicient while agitated III with air so as to remove the remaining moisture, heating the same at a temperature and for a period sufficient while agitated with steam to remove the fats and lighter hydrocarbons, vand ltering the residue.

2. In the art of reclaiming used mineral lubricating oil containing solid matter, moisture and li hter hydrocarbons, and partially emulsiiie and polymerized, the process comprising, defecating the oil to clear the same of the solimatter and entrained water, gradually heating the defecated oil to the vaporizing point of thlenineral lubricant base for a period suiclent to volatilize the remaining) moisture and lighter hydrocarbons, lowing the oil bodywhile ing so heated, first with air and then with steam,

and filtering the residue.

3. In the art of reclaiming used mineral lubricating oil containing solid matter, moistureand lighter hydrocarbons, and partially emulsilied and polymerized, .the process comprising, defecating' the oil to' clear the same ofthe solid matter and entrained water, gradually heatingl the defecated oil to the vapori'zing point of the min.- eral lubricant base for a period suicientto volatilze the remaining moisture and lighter hydrocarbons, blowingthe oil body while being so heated, first with air, -then with amixture of air and steam and then with alone,-and filtering the residue. f 4; In the art of reclaiming used mineral lubricating oil containing solid matter, moisture and lighter hydrocarbons, and par tially emulsiedmndpolymerized, the-process comprising, defecating the oi'l to clear the' same of the solid matter and entrained water,

gradually heating the defecated oil to the vaporizing pointv of the mineralvlubricant base for a period suilcient to volatilize the remainin moisture and lighter hydro carbons, lowing the oil bodywhile being so heated, first with air, then with a mixture of.

air and live steam, and then with superheated steam alone, and iiltering the residue.

A5. In the art of reclaiming used mineral lubricating oil 'containing vsolid matter,

f6. `In the art of reclaiming used mineral lubricating oil containing solid matter, moisture and 1i hter hydrocarbons and partially emulsife and polymerized, the process' comprising, defecating-the oil to clear the same of the solid matter and entrained water, i

gradually heating the defecated \oil to the vaporizing point of the mineral lubricant base for a period suicient to volatilize the remaining moisture and lighter-hydrocarbons, blowing the oil body while being so heated, first with air, then with a mixture of air and live steam and then with su erheated steam,

permitting the body to coo while agitated" with superhated steam, and filtering the residue 7. In\th`e art of reclaiming used mineral 4lubricating oil' containing solid matter,

moisture and lighter hydrocarbons and partially emulsied and polymerized, the process comprising, treating the oil bod with a mineral acid, treating the same with an alkali,

gradually heating the oil body so treated t0 the vaporizing plaint ofthe mineral lubricant base, blowing t e oil body while so heated, first with air, thenwith a mixture of air and steam and then with steam alone, and filterin the residue.'

testimony whereof I aix my signature this 27th day of December, 1922.

. y OLIVER VJ. NELSON.

moisture and lighter hydrocarbons, and partially emulsied and polymerized, the process comprising, defecating the oil to' clear 'theA same of the solid matter and entrained water,

gradually heating the defecated oil to the vaporizing b ase for a period suilicient tovolatilize the point of the mineral lubricantremaining moisture and lighter h drocar-v bons,

blowing the oil body while 'eing 'so heated, first with air,

permitting the body to cool-.while agitated with steam, and ltering the residue. 

